Evaluation of Alkali-Silica Reaction by Concrete Microbar Test

Different aspects of the proposed concrete microbar test that uses aggregate with an aggregate-cement ratio of 1:1, a water-cement ratio (w/c) of 0.33, and particle sizes between 4.75 and 12.5 mm (No. 4 and 11/2 in.) to evaluate alkali-silica reaction (ASR) expansion is investigated in this study. Different aggregate gradations were used to modify the concrete microbar test method. ASR expansions decreased when the coarsest aggregate size coarse aggregate fraction increased, considering no-fines mixtures. Adding fine aggregate to a concrete microbar mixture, however, increased expansions. Expansion values were not strongly affected by w/c alteration of these mixtures in the practical range. The accelerated mortar bar test and concrete microbar test methods were used to study how ASR expansions were affected by some supplementary cementing materials (natural zeolite powder, natural pozzolan, and fly ash). Comparable expansions were revealed through evaluations of supplementary cementing materials' effects on alkali-silica reaction expansion in both of the accelerated test methods.